Anti-phase cocontraction practice attenuates in-phase low-frequency oscillations between antagonistic muscles as assessed with phase coherence
Voluntary contraction of skeletal muscles involves common in-phase neural oscillations in low frequencies (around 1–2 Hz) across muscles. The purpose of this study was to determine if anti-phase antagonistic cocontraction practice can attenuate the occurrence of in-phase low-frequency oscillations in antagonistic muscle activity. For this purpose, we determined the probability density function of phase coherence in surface electromyogram (EMG) between antagonistic muscles. Healthy young adults were assigned to one of three intervention groups. They performed an isometric transient and steady cocontraction test with elbow flexors and extensors before and after a session of distinct intervention. In the Cocontraction group, subjects practiced alternating anti-phase isometric cocontraction with the flexors and extensors concurrently. In the Contraction group, subjects practiced alternating isometric contraction levels with flexors or extensors independently. Subjects in the Control group did not perform motor practice. The occurrence of in-phase coherence < 3 Hz during the cocontraction test (including transient and steady portions) was determined from the probability density function of phase coherence in rectified EMG between pairs of elbow flexor and extensor muscles. The change in the probability of in-phase coherence after the intervention period was greatest in the Cocontraction group, followed by Contraction group, and then Control group, on average. The Cocontraction group showed significantly greater reductions than the Control group across the cocontraction test portions. The results suggest that a session of anti-phase cocontraction practice can consistently attenuate the occurrence of in-phase low-frequency oscillations between cocontracting antagonistic muscles across steady and non-steady cocontractions in healthy young adults.
KeywordsAntagonist Common drive Correlated oscillations EMG Muscle coactivation
This material was supported, in part, by the National Science Foundation under Grant No. IIS 1317718. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
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